Former president Jimmy Carter remained hospitalized Wednesday in Cleveland, a day after he fell ill while on tour promoting his 26th book.

Both of the Washington events he had scheduled for Wednesday were canceled.

Carter, who will turn 86 on Friday, developed an upset stomach aboard a flight from Atlanta on Tuesday and was rushed by ambulance and Secret Service escort to MetroHealth Medical Center, where he remained overnight. President Obama called the 39th president in the afternoon and reported that Carter "sounded great," said White House spokesman Bill Burton.

But a statement posted mid-morning Wednesday on the Web site of the Carter Center said that although the former president was feeling "normal," he would remain hospitalized for "additional observation."

The episode added more drama to the bits of controversy Carter has created during interviews to promote "White House Diary," an edited collection of the journals he kept during his four-year term.

He said last week that his role as a former president is probably "superior" to those of other ex-presidents because of his independent dealmaking in trouble spots around the world. A month ago, for instance, he popped up in North Korea and won the release of an American teacher who had been imprisoned for illegally crossing the border.

Carter had been scheduled to appear Wednesday night at George Washington University's Lisner Auditorium for a book signing and a talk before a sold-out crowd of 1,400. As of Tuesday night, a spokeswoman for the event said they believed he would be able to be there.

Carter had also been scheduled to sign books at Politics and Prose in the District. His last signing, in 2003, drew about 750 people, said Mike Giarratano, who handles the store's author events.

Neither event was immediately rescheduled.

Carter's hospitalization disappointed about 500 people who had lined up Tuesday afternoon at Joseph-Beth Booksellers in Cleveland, according to reporters at the store. Carter also canceled an event Tuesday night in Durham, N.C.

The scheduled appearances were at the beginning of a 13-city tour for the book.